Radio antenna



RADIO ANTENNA Filed Aug. 5, 1954 2 Sheets-Sheet l A NJ i I l I INVENTOR. JOSEPH B.CEJKA j (373$,M RSOXNXRA.

ATTORNEYS June 24, 1958 J. B. CEJKA RADIO ANTENNA Filed Aug. 5, 1954 2 Sheets-Sheet 2 INVENTOR. JOSEPH B.CEJKA BY ATTORNEYS United States Patent'O RADIO ANTENNA Joseph B. Cejka, Highland Park, N. 1., assignor to General Bronze Corporation, Garden City, N. Y., a corporation of New York Application August 5, 1954, Serial No. 447,992 4 Claims. Cl. 343-715 The present invention relates to automobile ,radio antennas and more particularly to an antenna which can be extended to a relatively great height above its mounting on an automobile body, and which can be telescoped down so that only a very small length of the antenna projects.

An antenna embodying the present invention is adapted to be mounted on an automobile in a position which affords vertical'clearance space within the automobile beneath the mounting. For example, the antenna is well adapted for either cowl or fender mounting.

The invention is illustrated as embodied in an automobile antenna which is rugged, attractive in appearance, and which when telescoped extends but a small distance above the mounting surface and yet has minimum capacitance to the body of the automobile.

The various advantages and aspects of the invention will be more fully understood from the following description considered in conjunction with the accompanying drawings, in which:

Figure 1 is a front view partly in elevation and partly in section, of an antenna assembly embodying the invention, shown mounted on the body of an automobile;

Figure 2 is a side view partly in elevation and partly in section, of the mounting portion of the antenna assem bly of Figure 1;

Figure 3 is a section taken along line 3-3 of Figure 1;

Figure 4 is a section taken along line 4--4 of Figure 2;

Figure 5 is a sectional view taken along line 5-5 of Figure 4; and

Figure 6 is a sectional view on enlarged scale of a sealing bushing in the mounting portion of the antenna.

The antenna assembly comprises a telescoping antenna or signal-receiving portion 10, a mounting 12, a tubular mounting 14, and a tubular well 15, into which the antenna 10 extends when in its collapsed position. The antenna portion 10 includes a top rod section 16 with a corona tip 18, an intermediate tubular section 20, and a lower tubular section 22. Sections 16, 20, and 22 are of conventional construction and are arranged to telescope to permit the antenna to be lengthened or shortened.

A pair of arms 24 swingably mounted on lugs 25 on opposite sides of the tubular base 14 supported by shoulders 26 are arranged to grip the underside of the automobile body 27 on which the antenna assembly is mounted. A cap nut 28 is threaded onto the base 14 and bears against an insulator collar 30 and a resilient gasket 32 against the outside of the automobile body 26. The arms 24 are generally similar in construction and mounting to those described in U. S. patent application Serial No. 393,331, filed November 20, 1953, except for two upwardly extending prongs 38 on the ends of arms 24 which bite into the underside of the automobile body to insure a firm mechanical mounting and a low-resistance ground connection. v

To provide a watertight seal without excessive fric- 2,840,816: Patented June 24, 1958 tional drag a bushing 44 (see also Figure 6) of polyethylene or other suitable resilient insulating material, is positioned around the lower antenna section 22 and extends within the upper end of the tubular base 14. This bushing has an external flange 46 at its lower end which abuts an internal shoulder 45 in the base 14. The bushing 44 has an integral internal sleeve 48 that is joined to the remainder of the bushing 44 only at its upper end and is surrounded by an annular space 50 between the outer surface of the sleeve 48 and the inner surface of the surrounding portion of the bushing 44. The vertical opening 52 through the sleeve 48 for the antenna section 22 is of slightly smaller diameter at its upper end, with a tapered portion in the area indicated at 53 to form an etfective seal with the section 22, while the remainder of the sleeve forms a long internal surface leakage path that adds but little to the frictional drag of the antenna section 22 when it is moved upwardly or downwardly. When the nut 28 is tightened, the outer circumference of the bushing 44 is compressed somewhat to provide a tight seal, but this does not increase the frictional drag of the antenna because of the annular space 50 around the sleeve 48. The lower end of the inner sleeve 48 has an inner annular recess 54.

To provide a guide for the lower end of the antenna section 22, an insulaitng washer 55, slidable within the tubular well 15, is rotatably secured to the lower end of the antenna section 22, for example by reducing the diameter of the lower end of the section 22, passing it through a central opening in the washer 55, and peening over its tip on the lower side of the washer 55.

As shown in Figures 1 and 3, the Washer 55 includes an inner metal sleeve 56 embracing the end of the antenna section 22, a thin web 57 surrounding the sleeve 56 and having three holes 58 in it forming three spokes to increase the resiliency with which the lower end of section 22 is supported within the well 15. The rim 59 of this washer has an axial length about three times the thickness of the web 57 with the top and bottom flanges of the rim being symmetrically tapered on the inside over their full length for greater strength, and with short tapered surfaces 60 on the outside of the edge of the rim to facilitate the sliding of the washer 55 within the Well 15. To further facilitate its sliding, the rim 59 has a circumferential groove 61 and three evenly spaced axial grooves 62.

To limit the downward movement of the antenna section 22, a cup-shaped stop 63 is staked inside and near the lower end of the well 15 by evenly spaced indentations 64 in the wall of well 15, three indentations being above and three below the rim of the stop 63. When the antenna is fully retracted, the washer 55 rests upon the stop 63.

The upper end of the antenna well 15 is secured in a socket 69 in the base 14 and aligned with the bore of the base 14, by three self-tapping screws 65, two of which connect the top of well 15 to a tongue portion 66 extending downwardly on one side from the main body of the base 14, and one of which engages the main body of the base 14.

In order to provide a connection between antenna 10 and the automobile radio receiver (not shown) a high Q, low-capacity, coaxial cable 67 is secured by a coupling nut 68 to a nipple 70 on the tongue portion 66 position. A terminal screw 80 extends through the center of the contact 76 and its shank 81 forms the center terminal for engaging the center terminal of the socket 70.

In order to provide support for antena section 22 to hold it firmly in line with the spring member 76, the insulator spacer 78 has a curved pillow 82 on the opposite side of section 22 from the nipple 70. A tubular projection 84 on the insulator 78 fits intonipple 70 to form an insulating lining around the screw 80 and the shank 81; a radial hole 85 in the insulator '78 aligned with projection 84 engages the threads of the screw 80 and supports it and the spring member 76. Access to the screw 80 is provided by a hole 86 passing through pillow 82 of the insulator 78.

In assembly, the projection 84 is slid into the nipple 70, and then the well is slid up into place in the socket 69 with a wide longitudinal slot 87 in the top of well 15 straddling the projection 84, as seen in Figure 2. Thus the antenna structure is quickly assembled and held together merely by engaging the parts and inserting the screw 65.

The lower end of the well 15 may be braced by a collar 88 and strap 90 secured to the automobile frame, by means of a screw hole 92. The well 15 may be seamless tubing or may have a folded seam, not shown, one of the vertical recesses 56 in washer 48 straddling the seam for clearance.

In a particular commercial form the following dimensions and materials were used, and these details are set forth to provide a specific example of a successful embodiment of the present invention to enable those skilled in the art better to use the invention. The antenna section 16 is a 0.100 inch diameter stainless steel rod, sections and 22 are, respectively, 0.218 and 0.312 inch in diameter formed of admiralty brass tubing, bright chromium plated. Bushing 44 is a molded black polyethylene, with the outside diameter of the flange 46 being 0.874 inch, the outside diameter of the body of the,

bushing being 0.720 inch, the inside diameter of the outer sleeve being inch, the outside diameter of the sleeve 48 being 7 inch. The top of the flange and bushing body are both chamfered at a angle to the vertical. The base 14 is die cast from Zamak No. 3 with an overall length of about 3% inches, with the distance from the center of the nipple 70 to the top edge of the base being 2 inches. 1% inches, the inside diameter of the bottom socket 64 which receives the top of the Well 15 being 1.010 inches, with tongue 65, as seen in section in Figure 4, covering an angular arc of 135. The inside diameter of the center portion of the base 14 is inch, and the inside diameter above the inner shoulder is 0.880 inch. The centers of lugs 25 are 1% inches down from the top of the base 14 and they are 0.200 inch in diameter and project of an inch. The recesses above the shoulders 26 are .065 inch deep and have a 5 undercut on their bottom edges 0.468 inch below the centers of the lugs 25 so as better to grip the rounded lower shoulder portions on the arms 24.

The inside diameter of the nipple 74 is ,6 of an inch. The Washer 48 and the insulator spacer 78 are of molded black polyethylene.

The well 15 is a one inch outside diameter seamed aluminum tube with a wall thickness of .035 inch and a length of about 15% inches so that when it is assembled the overall length of the base and well from the top of bushing 44 to the bottom of the well is only 17% inches. When extended, this antenna projects 57 inches above the top of'the bushing 44 and when collapsed extends only 8 inches above this bushing.

objects set forth.

The outside diameter of the base 14 is What is claimed is:

1'. A- collapsible automobile radio antenna assembly comprising an antenna portion including a plurality of extensible telescoping sections, a base portion, having a longitudinal bore therethrough, mounting means for securing said base portion to an automobile body with said longitudinal bore projecting outside of said body, said base having a socket therein aligned with said bore, a tubular well secured in said socket and projecting from said base, one of said antenna sections extending from the outside of said body through said bore in said base and into said tubular well, a first insulator element slidably fitting within said well portion and supporting said one antenna section in spaced longitudinal relation within said well, a second insulator element secured within said base and slidably supporting said one antenna section in longitudinal spaced relationship within its bore, a third insulator element intermediate said first and second insulator elements and secured within said base portion in fixed position, said third insulator element having an opening therethrough through which said one antenna section projects, said third insulator element in cluding a pillow portion within said opening engaging one side of said one antenna section, a spring contact longitudinal bore therethrough, said base portion having.

a neck, said bore passing longitudinally through said neck, mounting means for securing said base portion to an automobile body with said neck projecting outside of said body, said base having at its lower end a socket aligned with said here, a tongue portion projecting: longitudinally from said base in the opposite direction from said neck, a threaded nipple on said tongue, connection means projecting inwardly from said nipple into said socket, a tubular well having a longitudinal slot in one. I

end, said end being secured in said socket with its opposite end projecting from said base, said slotstraddling.

said connection means, one of said antenna portions extending from the outside of said body through said opening in said base and through said socket into said tubular well, a first insulator element secured to said one antenna element and slidably supporting said one antenna section in spaced longitudinal relation within said well, a second insulator element securedwithin the neck of said base and slidably supporting said one antenna section in longitudinal spaced relationship within its bore, and a third insulator element within said socket, and a contact element secured to said third insulator element and slidably engaging said one antenna section and in electrical engagement with said connection means.

3. An automobile radio assembly as claimed in claim 2 and wherein said third insulator element has an opening therein through which'said one antenna section projects, said contact element being secured within the opening of. said third insulator element. 7

4. A collapsible automobile radio antenna assembly comprising an antenna portion including a plurality of extensible-telescoping sections, a base having a longitudinal bore therethrough, a neck portion on said base, said bore passing through said neck portion, mounting means for securing said base portion to an automobile body with said neck portion passing through the exterior of said body, said base having a socket therein aligned with said bore, a tubular well having oneend' secured in said socket and the other end projecting from saidbase, the

passage in said well being aligned with saidbore, one

of said antenna sections extending from the outside of said body through said bore of said base and into said tubular well, an insulator washer secured to the lower end of said one antenna section and slidably fitting Within said Well portion and supporting said one antenna section in spaced longitudinal relation within said well, said washer comprising a hub portion around said end of said one antenna section, a perforated annular web portion surrounding said hub portion, and a rim portion surrounding said web portion and having an axial length greater than the thickness of said web portion, said rim being tapered radially inwardly on its outer surface adjacent both of its edges, a plurality of axially extending recesses in the outer surface of said Washer, and a circumferential recess in the outer surface of said washer, an insulator bushing around said one antenna section in said neck portion and slidably supporting said one antenna section in longitudinal spaced relationship within the References Cited in the file of this patent UNITED STATES PATENTS 2,239,614 Martin Apr. 22, 1941 2,632,106 Carlson Mar. 17, 1953 2,634,370 Carlson Apr. 7, 1953 2,688,698 Gosline Sept. 7, 1954 

